Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 14-16

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 37-39

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 39-41

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 41-42

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 51-52

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 80-86

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 198-203

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 207-209

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 209-212

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 213-221

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 222-223

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 223-236

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 249-251

Published in Journal of the Washington Academy of Sciences, in 1931, in volume 21, pages 251-253

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 259-261

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 262-263

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 288-294

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 298-301

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 301-304

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 305-308

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 309-314

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 320-325

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 336-339

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 354-355

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 390-397

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 397-405

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 405-407

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 416-426

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 427-429

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 430-436

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 436-437

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 482-483

Published in Jour Washington Acad Sci, in 1931, in volume 21, pages 513-526

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 526-530

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 530-535

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 536-538

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, pages 539-640

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, issue 4, pages 49-51

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, issue 7, pages 144-152

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, issue 12, pages 264-276

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, issue 14, pages 325-336

Published in Journal of The Washington Academy of Sciences, in 1931, in volume 21, issue 15, pages 347-353

Published in Journal of the Washington Academy of Sciences, in 1931, in volume 21, issue 20, pages 485-488